The existing network of coaxial cable television wiring was once foreseen as providing the primary high-speed infrastructure for linking computers and computerized televisions to sources of information such as the Internet. However, it is becoming apparent that the availability of such cable-based information access will not be realized in the near term, if ever, particularly as competing high-speed transmission media (such as that based on higher quality telephone lines, faster modems and ISDN technology) become entrenched. Indeed, the current economic climate has made it impractical, or at least extremely risky, for cable television service providers to replace their existing base of possibly tens or even hundreds of thousands of receive-only cable set-top converter boxes with computerized transmit-and-receive cable modems. However, such two-way cable modems are needed to provide subscribers with interactive television and a real-time, high-speed link to information services, while simultaneously providing conventional television programming thereon.
At the same time, it is certain that many cable subscribers simply want low-cost television programming. This leaves cable providers with the dilemma of losing subscribers if they raise prices in order to upgrade their systems, or being left behind by new competitors and competing technologies if they do not. One solution is to convert to new technologies gradually. For example, conventional television programming can now be transmitted over cable in a digital format, enabling the transmission of many more (virtual) channels on the same bandwidth cable. Rather than force all subscribers to convert to the digital format, however, cable service providers will transmit a mixture of analog and digital signals for a period of time. This reduces the total number of channels transmitted to less than the maximum possible allowed by the bandwidth, but allows the cable companies to keep subscribers who are reluctant to convert.
Regarding information services on the television, a number of low-cost devices presently exist for allowing access to information services using a television set instead of a computer monitor. However, these devices do not approach interactive television, but instead do little more than use the television display as an inexpensive monitor while connecting to the information service via a conventional, telephone-based modem. As a result, with such a device there is no direct connection between programs transmitted to a viewer and interaction with web pages or the like about those programs. For example, a viewer of a home shopping channel wishing to purchase a displayed item cannot simply do so with the low cost-device, but instead must first connect to the information service (e.g., the Internet) via the user's service provider, find the shopping channel's web-site (if one exists), find the appropriate item (if available on the web-site) and then place the order. Most significantly, these devices tie up a telephone line for long periods of time, a significant drawback in many households.